The "Cool Ghoul," as he was known, delighted fans for decades as the late-night television host "Roland" (pronounced ro-LAND) in Philadelphia and "Zacherley" in New York City, later becoming one of America's top FM DJs.

Mr. Zacherle, a Germantown native, died Thursday of natural causes in his apartment near Central Park in New York City. He was 98 and had only recently cut back on convention appearances at which legions of fans flocked to hear his maniacal laugh and signature signoff, "Good night, whatever you are."

"He was the most generous, nicest, and kindest man I've ever known," said a longtime friend, Jeff Samuels. "He just loved life - and what an incredible life he had."

Mr. Zacherle grew up on Pulaski Avenue in Germantown and graduated from Germantown High School and the University of Pennsylvania, then served as an Army captain in England and North Africa in World War II.

His uncle, Robert Eneas Lamberton, was a mayor of Philadelphia who died in office in 1941.

Mr. Zacherle's broadcasting career began at WCAU-TV in Philadelphia, where he was hired as an actor playing several roles (including that of an undertaker) in the western series Action in the Afternoon.

In a Daily News profile in 2015, Mr. Zacherle laughed about the production of that show.

"They would be taking a picture of someone riding across the countryside on a horse and someone else would be driving by in a brand-new Cadillac," he said.

Three years later, he was hired as the host of WCAU's Shock Theater. He wore a long, black, undertaker's coat as the character "Roland."

Mr. Zacherle said he got the gig because he already had an undertaker's outfit.

In 1958, with Dick Clark's backing, Mr. Zacherle cut "Dinner with Drac" for Cameo Records. The song reached No. 8 on the Billboard pop chart.

He relocated to New York City in 1959, changing the character from "Roland" to "Zacherley," hosting Shock Theater.

Mr. Zacherle sometimes filled in for Clark when the Philly-based AmericanBandstand went on the road in the 1960s.

It was Clark who reportedly dubbed Roland the "the Cool Ghoul," and it stuck.

In a 1960 promotional stunt for his move to WOR-TV, Mr. Zacherle staged a presidential campaign. His "platform" recording can be found on the album Spook Along with Zacherley, which originally included a Zacherley for President book and poster set - a collectible in great demand today.

He hosted animated cartoons and Chiller Theatre on WPIX in New York in 1963, and a year later he began hosting a teenage dance show at WNJU-TV in Newark called Disc-O-Teen, including the teenage show participants in skits. It lasted three years.

"I went from one station to another in New York, showing the scary movies," he told the Daily News last year. "It was very easy, they'd say, 'We got a lot of old movies,' and I'd say, 'Let's do it.' It was great and people really enjoyed watching it because there was a lot of comedy in it."

Mr. Zacherle's style - cutting in with silly skits while the movies were playing - influenced other shows, including Dr. Shock, Elvira, and Mystery Science Theatre 3000.

"I really wasn't trying to scare people. We were kidding around mostly," he said in 2015. "They were supposedly scary movies but I usually hadn't seen them until we sat down in the room and took a look at them for the show."

In 1967, he became a morning radio host for WNEW-FM. Two years later, he became the station's night broadcaster from 10 p.m. to 2 a.m. when the station turned to a progressive rock format. In 1971 he switched his show to WPLJ-FM, where he remained for a decade.

Mr. Zacherle was inducted into the Broadcast Pioneers of Philadelphia's Hall of Fame in 2010.

"In his day, he was one of the first superstars of radio and television in the Delaware Valley," said Gene Kolber, a member of the Broadcast Pioneers.

Kolber said he invited Zacherle, as Roland, to make an appearance in the early 1960s at a business in Allentown, where Kolber was a radio host, and chaos ensued.

"They had to call the police to control the crowds," he said.

Mr. Zacherle never married. He is survived by three nieces; and five great-nieces and nephews.

Niece Linda Zacherle Marston said her uncle cared for many family members when they grew ill and often hopped into his Volkswagen Beetle and drove for hours to visit friends and relatives.

"He was always just Uncle John to us," Marston said. "People didn't always know what he was really like, but he was the sweetest man."